Search Publications
An Ensemble Study of a January 2010 Coronal Mass Ejection (CME): Connecting a Non-obvious Solar Source with Its ICME/Magnetic Cloud
Webb, D. F.; Möstl, C.; Farrugia, C. J. +9 more
A distinct magnetic cloud (MC) was observed in-situ at the Solar TErrestrial RElations Observatory (STEREO)-B on 20 - 21 January 2010. About three days earlier, on 17 January, a bright flare and coronal mass ejection (CME) were clearly observed by STEREO-B, which suggests that this was the progenitor of the MC. However, the in-situ speed of the ev…
Two-Way Frequency Fluctuations Observed During Coronal Radio Sounding Experiments
Pätzold, M.; Bird, M. K.; Efimov, A. I. +5 more
Coronal radio-sounding experiments were carried out using two-way coherent dual-frequency carrier signals of the ESA spacecraft Rosetta (ROS) in 2006. Frequency measurements recorded at both NASA and ESA tracking stations (sample rate: 1 Hz) are analyzed in this work. Spectral analysis of the S-band, X-band, and differential frequency records has …
The Interaction Between Coronal Mass Ejections and Streamers: A Statistical View over 15 Years (1996 - 2010)
Llebaria, A.; Lamy, P.; Floyd, O.
We report on the statistical analysis of the interaction between coronal mass ejections (CMEs) and streamers based on 15 years (from 1996 to 2010 inclusive) of observation of the solar corona with the LASCO-C2 coronagraph. We used synoptic maps and improved the method of analysis of past investigations by implementing an automatic detection of bot…
Exploring the Capabilities of the Anti-Coincidence Shield of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) Spectrometer to Study Solar Flares
Klein, K. -L.; Vilmer, N.; Hamadache, C. +3 more
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is a European Space Agency hard X-ray/γ-ray observatory for astrophysics, covering photon energies from 15 keV to 10 MeV. It was launched in 2002, and since then the Bismuth Germanate (BGO) detectors of the Anti-Coincidence Shield (ACS) of the Spectrometer on INTEGRAL (SPI) have detect…
North-South Asymmetry in the Distribution of Solar Background Magnetic Field
Obridko, V. N.; Chertoprud, V. E.; Kuzanyan, K. M.
The aim of this article is to investigate how the background magnetic field of the Sun behaves in different hemispheres. We used SOHO/MDI data obtained during a period of eight years from 2003 to 2011 to analyze the intensity distribution of the background magnetic field over the solar surface. We find that the background fields of both polarities…
Simulated (STEREO) Views of the Solar Wind Disturbances Following the Coronal Mass Ejections of 1 August 2010
Feng, X. S.; Zhang, Y.; Dryer, M. +7 more
Images observed by the twin spacecraft Solar TErrestrial RElations Observatory (STEREO) A and B appear as complex structures for two coronal mass ejections (CMEs) on 1 August 2010. Therefore, a series of sky maps of Thomson-scattered white light by interplanetary coronal mass ejections (ICMEs) on 1 August 2010 are simulated using the Hakamada-Akas…
Phase Relationships Between the CME-Energy Cycle, the Sunspot-Area Cycle and the Flare-Index Cycle
Zhong, J.; Xie, J. L.; Gao, P. X.
We study the phase relationships between the coronal-mass-ejection (CME) energy cycle, the sunspot-area cycle, and the flare-index cycle from 1996 to 2010. The results show the following: i) The activity cycle of the flare index significantly leads the activity cycle of the sunspot area. ii) The activity cycle of the CME energy is inferred to be a…
A Change in the Solar He II EUV Global Network Structure as an Indicator of the Geo-Effectiveness of Solar Minima
Gurman, J. B.; Didkovsky, L.
Solar activity during 2007 - 2009 was very low, causing anomalously low thermospheric density. A comparison of solar extreme ultraviolet (EUV) irradiance in the He II spectral band (26 to 34 nm) from the Solar Extreme ultraviolet Monitor (SEM), one of instruments on the Charge Element and Isotope Analysis System (CELIAS) on board the Solar and Hel…
The Evolution of the Net Twist Current and the Net Shear Current in Active Region NOAA 10930
Venkatakrishnan, P.; Ravindra, B.; Jaaffrey, S. N. A. +1 more
The electric current exists because of the non-potential magnetic field in solar active regions. We present the evolution of net current in the solar active region NOAA 10930 as the sum of shear current and twist current by using 27 high-resolution vector magnetograms obtained with Hinode/SOT-SP during 9 - 15 December 2006. This active region was …
The Late Gradual Phase of Large Flares: The Case of November 3, 2003
Auraß, H.
The hard X-ray time profiles of most solar eruptive events begin with an impulsive phase that may be followed by a late gradual phase. In a recent article (Aurass et al. in Astron. Astrophys.555, A40, 2013), we analyzed the impulsive phase of the solar eruptive event on November 3, 2003 in radio and X-ray emission. We found evidence of magnetic br…